1 /*
2 * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
3 * University Research and Technology
4 * Corporation. All rights reserved.
5 * Copyright (c) 2004-2005 The University of Tennessee and The University
6 * of Tennessee Research Foundation. All rights
7 * reserved.
8 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
9 * University of Stuttgart. All rights reserved.
10 * Copyright (c) 2004-2005 The Regents of the University of California.
11 * All rights reserved.
12 * Copyright (c) 2009 Cisco Systems, Inc. All rights reserved.
13 * Copyright (c) 2015 Research Organization for Information Science
14 * and Technology (RIST). All rights reserved.
15 * $COPYRIGHT$
16 *
17 * Additional copyrights may follow
18 *
19 * $HEADER$
20 */
21 /** @file */
22
23 #include "ompi_config.h"
24
25 #include "ompi/constants.h"
26 #include "ompi/communicator/communicator.h"
27 #include "coll_sm.h"
28
29
30 /**
31 * Shared memory allreduce.
32 *
33 * For the moment, all we're doing is a reduce to root==0 and then a
34 * broadcast. It is possible that we'll do something better someday.
35 */
36 int mca_coll_sm_allreduce_intra(const void *sbuf, void *rbuf, int count,
37 struct ompi_datatype_t *dtype,
38 struct ompi_op_t *op,
39 struct ompi_communicator_t *comm,
40 mca_coll_base_module_t *module)
41 {
42 int ret;
43
44 /* Note that only the root can pass MPI_IN_PLACE to MPI_REDUCE, so
45 have slightly different logic for that case. */
46
47 if (MPI_IN_PLACE == sbuf) {
48 int rank = ompi_comm_rank(comm);
49 if (0 == rank) {
50 ret = mca_coll_sm_reduce_intra(sbuf, rbuf, count, dtype, op, 0,
51 comm, module);
52 } else {
53 ret = mca_coll_sm_reduce_intra(rbuf, NULL, count, dtype, op, 0,
54 comm, module);
55 }
56 } else {
57 ret = mca_coll_sm_reduce_intra(sbuf, rbuf, count, dtype, op, 0,
58 comm, module);
59 }
60 return (ret == OMPI_SUCCESS) ?
61 mca_coll_sm_bcast_intra(rbuf, count, dtype, 0, comm, module) : ret;
62 }